Currently, LED (light-emitting diode) is increasingly used as a backlight module for electronic devices such as TV and computer screens. En general, characteristics of LED would change after a longtime working of the electronic device, that is, required voltage to light the LED would slowly increase according a curve with time, so the output voltage of the LED light backlight driver circuit would gradually rise. At present, values of OVP (Output Over-voltage Protection), OCP (Input Over-current Protection) are all set in advance, and it is difficult to change, thus the OVP and OCP values should be relatively low when the output voltage of the LED light backlight driver circuit gradually rise, which results the protection function be triggered abnormally but the LED works properly.